In a background related to an environment problem and an energy problem, a demand that a vehicle or an industrial apparatus are controlled faster and higher accurately to suppress an exhausted gas or to reduce an amount of energy used increases. A digitalization of a control circuit to control the vehicle and the industrial apparatus has been advanced. In general, an analog signal outputted by a sensor that detects a physical condition of an apparatus is converted to a digital signal by an A/D (analog/digital) convertor (ADC), and then the apparatus is controlled with a result of digital signal process. Therefore, a demand to a high speed and high accurate ADC has grown.
For example, in order to reduce the nonlinearity error of the A/D conversion caused by an error of a capacity value of a capacitive element configuring an ADC, a successive approximation register (SAR) type ADC in Patent Literature 1 is configured to perform a dithering to the capacity used when the A/D conversion is performed.
On the other hand, the ADC as described in Patent Literature 2 and Non-patent Literature 1 is a delta sigma type A/D convertor that has implemented high accuracy by using a delta sigma (ΔΣ) modulation.
In addition, the A/D convertor as described in Patent Literature 3 is an incremental delta (incremental Δ) type A/D convertor to vary a feedback amount by an analog quantizer.